Recently, the area of a memory capacitor has been reduced and the absolute value of capacitance has been also reduced in accordance with miniaturization of a semiconductor device. The capacitance C, for example in the case of a parallel-plate capacitor structure, is determined by C=∈·S/d, wherein ∈ means the dielectric constant of a capacitor insulating film, S means the area of an electrode, and d means the film thickness (distance between electrodes) of a dielectric. In order to assure a capacitance value without increasing the area S of an electrode used for a capacitor element for information accumulation, it is necessary to use a capacitor insulating film material having a high dielectric constant ∈ or to decrease the film thickness d of a capacitor insulating film.
Heretofore, a silicon oxide film has been used as a capacitor insulating film, and high integration has been carried out by decreasing the thickness of this film. However, in a highly integrated memory of not less than 256 megabits, reduction of the film thickness has been put to the limit, and, therefore, there has been introduced a capacitor insulating film material such as tantalum oxide that has a higher dielectric constant E than silicon oxide. Furthermore, in a DRAM (Dynamic Random Access Memory) of not less than 1 Gbit, there has been considered use of a high dielectric constant material of barium strontium titanate (BaxSryTisOt:BST) as disclosed in, for example, JP-A-9-186299. The similar problem is applicable to not only a highly integrated memory but, also, with regard to a condenser used for various electronic circuits requiring miniaturization. For example, as disclosed in JP-A-10-41467, there has been considered use of titanium oxide having a high dielectric constant as a capacitor insulating film material for a condenser.